There are several options in the immediate SeaWorld area. Off the top of my mind are the following, but I may be missing a couple of others in the general neighborhood...
Renaissance Orlando Resort is across the street from the SeaWorld parking lot - probably the most expensive option of the area hotels but, IMO, the nicest as well.
Hilton Garden Inn is a few yards further away, across a side street and a bit behind the Renaissance.
There's a Marriott Residence Inn, off Westwood Boulevard, about a mile from SeaWorld.
There's a SpringHill Suites on International Drive adjacent to the SeaWorld property and a Fairfield Inn across I-Drive from the SpringHill. And that Doubletree a bit further up I-Drive but still quite close to SeaWorld.
And several other hotels of varying prices up in the Convention Center area.
Dick Taylor